The present invention generally relates to the field of liquid-crystal displays (LCDs), and more particularly to a method and apparatus for monitoring LCD driver performance.
There are many applications in which it is desirable to be able to monitor the performance of the driver circuitry of a liquid-crystal display to ensure high integrity performance of the display. For example, in an avionics environment, a liquid-crystal display may be utilized as a primary flight display (PFD) where information vital to the operation of the craft is displayed. The analog nature and the complexity of the display drivers for liquid-crystal displays renders accurate monitoring of the operation of the display drivers difficult. Precise monitoring of the performance of the display drivers is therefore critical to ensuring the liquid-crystal display panel is properly functioning.
Previous implementations of LCD driver monitoring circuits typically provided a simple digital feedback signal merely indicating whether the input shift register of the display driver was operational. However, the only useful information provided by such a display driver monitoring system was whether or not the driver had suffered a catastrophic failure which would have been readily apparent to the user in any event in that the display would be inoperative. No LCD driver monitoring system known to date provides an analog monitoring system which monitors the actual analog output voltage for individual display driver output pins.